The mystical field surrounding a 1980s home computer, mainly the Sinclair ZX Spectrum, that must not be disturbed whilst the computer is loading software from audio cassette tapes. Some people performed highly sophisticated rituals to prevent loading errors, and others were convinced that games would not load properly if their mum asked them if they wanted a cup of tea whilst loading.
Coined in the late 90s by a poster on comp.sys.sinclair, who mis-typed "chutney" - the word was then adopted by a fellow poster to describe the phenomenon above.
"Where Time Stood Still had only three seconds left to load, when my brother came into the room, tripped over and ruined the chuntey field. I was gutted."